Auto parts are commonly build in very large manufacturing plants, using machines that are at once very large and very expensive. A typical auto parts example is shown on FIG. 1, which is a perspective view of a car side window detailing a pair of car window sweeps. An outer sweep 10 and an inner sweep 12 are located at the bottom of a window frame 14, on each side of a glass window pane 16. In order to limit as much as possible water leakage inside a door 18 under variable climatic conditions, the outer and inner sweeps 10 and 12 are made of steel-reinforced rubber profiles. Blank profiles are initially formed by extrusion. Their extremities are then cut into complex notch patterns in order for the outer and inner sweeps 10 and 12 to mate with various internal components (not shown) of the door 18.
FIG. 2 is a highly schematic top view of a conventional multi-pallet notching unit. FIG. 3 is a highly schematic side elevation view of the conventional multi-pallet notching unit of FIG. 2. Considering at once FIGS. 2 and 3, a notching unit 20 typically includes 12 pairs of cutting tools 22, six (6) on each side of the notching unit 20 (one row of cutting tools 22 is not shown on FIG. 3 in order to not hide other elements of the notching unit 20). Each cutting tool 22 is adapted to cut a different notch into ends of blank inner sweeps 24 and ends of blank outer sweeps 26. Pairs of blank inner and outer sweeps 24 and 26 are attached to pallets 30. A plurality of pallets 30 are mounted on an infinite belt 32. Each pair comprising one blank inner sweep 24 and one blank outer sweep 26 is attached by an operator 28 to a respective pallet 30 as a movement of the infinite belt 32 brings that pallet 30 at an end 34 of the notching unit 20. As first pallet 301 then reaches a first station 1 of six (6) stations 1-6, a first cutting tool 221 moves laterally inward of the notching unit 20 to cut notches (not shown) on right ends of the blank inner and outer sweeps 24 and 26 before returning to its initial, resting position. Concurrently, a second cutting tool 222 opposite the first cutting tool 221 moves laterally inward of the notching unit 20 to cut notches (not shown) on left ends of the blank inner and outer sweeps 24 and 26 before returning to its initial, resting position. The first pallet 301 moves forward to a second station 2 by action of the infinite belt 32. At the same time, another pallet 302 reaches the first station 1.
The illustrated notching unit 20 includes 12 cutting tools 22 that each are capable of moving laterally in synchrony with a movement of the infinite belt 32, for cutting up to six (6) notches at each end of the blank inner and outer sweeps 24 and 26. These movements require the notching unit 20 to include at least 13 motors (not specifically shown), one for each of the 12 moving cutting tool 22 and an additional one, usually larger, for running the infinite belt 32. Generally, these 13 motors are servo controlled motors to ensure proper synchrony of all components of the notching unit 20.
A typical notching unit such as the notching unit 20 is at once very expensive, in a large part because of the cost of its numerous servo controlled motors, and very bulky, occupying very significant floor space of an auto part manufacturing plant. A typical notching unit is actually wider than most standard transport containers and requires special means for delivery from its point of fabrication to the auto part manufacturing plant.
The operator 28 places blank inner and outer sweeps 24 and 26 on each pallet 30 that passes at the end 34 of the notching unit 20. If the operator 28 does not complete this operation in time before a given pallet 30 is moved into the first position 1, the operation of the notching unit 20 may need to be stopped, or at least slowed down, either automatically or command of the operator 28. Alternatively, the operation of the notching unit 20 may continue in the absence of one or both of the blank inner and outer sweeps 24 and 26 on the given pallet 30, which would be an inefficient use of the notching unit 20.
It is rare that a typical notching unit will be dedicated to manufacturing a unique type of car window sweeps. The various cutting tools 22 of the notching unit 20 are conventionally dismounted and replaced with other sets of cutting tools 22 whenever there is a need to manufacture car window sweeps for another car model. In fact, different pairs of car window sweeps are required for each of the four (4) doors of a typical sedan. Changing a set of up to 12 cutting tools 22 may require several hours of downtime of the notching unit 20.
Therefore, there is a need for improvements that compensate for at least some of the problems related to cost, size and maintenance needs of typical notching units.